Gearheads talk tech on the GTO Email list and I wish I understood half of it!
Q: I have a 1968 gto with a Y4 block in it, the heads are 6x.
Is that correct?
A: I have two Y4 engines and both are 455s and have 7M5 heads. I think that this is one of the correct configurations on a Y4 block. It sounds as though the 6Xs were transplanted on there. The quick way to tell a 455 from a 400 is to look for the transfer lug (cast pyramid) protruding out of the block to the left of the distributor. 400's did not have the transfer lug. Neither did 389's, but they have only two freeze out plugs in the side of the engine vs. 3 on the 400. Also, look under the engine below the exhaust manifold on the right side (starter side) and toward the front and you will see the "455" cast in the block. - John Hugentober
Q: Was the Ram Air III engine available in 1968?
A: The Ram Air III was not offered until 1969. However, Ram Air I & II engines were available in 1968. The Ram Air engines should also have the long branch swept back cast iron exhaust manifolds. Look for the head casting number on the center exhaust ports. The Block number will be stamped on a pad on the front of the block above the water pump.
Q: What engine and transmission combinations were available in
1968 and 1969?
A: See this chart...
Engine Trans Block C.R. Cam Head Designation
400/360hp M WS 10.75 068 16 400 H.O.
400/360hp A YZ 10.75 067 16 400 H.O.
400/360hp M XS 10.75 744 31 Ram Air I ##
400/360hp A XP 10.75 068 31 Ram Air I ##
400/360hp M WY 10.75 041 R(96)A Ram Air II
400/360hp A XW 10.75 041 R(96)A Ram Air II## The "31" cast into the head is sometimes mistaken for a "37"
Production numbers for 1969 Ram Air GTOs by Block Code:
XS = 650
XP = 158
WY = 199
XW = 47There were 92 M.T. Ram Air & 22 A.T. Ram Air convertibles.
Engine Trans Block C.R. Cam Head Designation
400/350hp M WT 10.75 068 48 non R.A.
400/350hp A YS 10.75 067 16/62 non R.A.
400/366hp M WS 10.75 744/068 48 Ram Air III **
400/366hp A YZ 10.75 068 16 Ram Air III
400/370hp M WW 10.75 041 722 Ram Air IV
400/370hp A XP 10.75 041 722 Ram Air IV** The 744 cam was used through engine #709185 then changed to the 068 cam.
WS = 6,392 (249 conv.)
YZ = 2,099 (113 conv.)
WW = 594 (45 conv.)
XP = 165 (14 conv.)Above figures include Judges also.
Q: I've been studying engine codes, head codes and compression
charts. I found that #94 heads were listed on 1966 326 250HP as well as
what you said below.
A: Those are #094 heads. Big difference between those & your #94's. The intake valve is even smaller at 1.92" and the combustion chamber is only 65cc vs. your #94's 90cc. A 65cc head on a 400 would give ~11.0 c.r. -- *WAY* too much for pump gas.
Q: If thats the case should I keep the heads and look for a 66
tri power set up???
A: No. BUT, in my opinion the '66 Tri-Power manifold was the best of that design series ('64 thru '66). The '64 & '65 manifolds used a smaller center carb; the '66 used the same size carbs in all three positions.
FYI: Tri-Power manifold numbers
1964 -- 9775088
1965 -- 9778818
1966 -- 9782898If you decide to go with a Tri-Power setup, be prepared to spend BIG $$$.
Q: Whats the difference between running a tri power vs. a 4bbl????
A: Not a whole lot from a performance standpoint. For the "ooh..ahh" kewlness Drive-In points, it is hard to beat a nice Tri-Power. When GM brought out the Q-Jet in '67, they had a 4-bbl carb that would flow the required air/fuel necessary to feed a hungry Poncho and the 3x2 setup was no longer needed.
Q: Do the numbers/markings on the front and back of the heads
mean anything? I was told only the center number tells which head it is.
A: Those numbers are usually forging numbers and other internal info., but not always. For example: the '67 Ram Air head #997 has the number cast under the #4 or #5 spark plug hole. The #191/197 head had the cast number on the end exhaust port. - Ken Carothers
Q: This has nothing to do with engines, but do you know how many
GTOs were painted my color?
A: Nobody knows. If someone DOES have a breakdown by color, they're keeping it a secret.
Q: I have heard that some brands of headlights don't fit into
the electrical sockets correctly. Is this true?
A: You should use Wagner brand headlights for a correct fit. That way your original light socckets will plug right on. The Wagner design is a duplicate of the original lights. Sylvania headlights have connector prongs that are not long enough. The sockets will not push onto the prongs with a firm grip. The problems you may notice will be dim lights and an inconsistent connection while driving on bumpy roads. If you are unlucky enough to purchase the Sylvania brand of headlights, you can modify the sockets to fit somewhat. Take a razor knife or Dremel tool and cut away about 1/8 inch of plastic material from the flared part of the socket all the way around. That will make it so the plastic socket will push all the way onto the headlight. Also, I recommend upgrading to halogen lights. They are brighter and safer.
Q: I would like to remove the starter from my 1968 GTO however
there are several things in the way. It still has the nose support bracket
which is one of the major problems. I can't get a wrench up in there to
remove the bracket and even if I could it probably wouldn't come loose.
So what is the best procedure for removing the starter?
A: Remove the cover on the torque converter. It is the big metal cover behind the starter. It is held on by about four bolts. Those are easy to take off. Remove the small nut on the front starter bracket. Most cars have the bracket, some do not. The bracket will then stubbornly push forward about a half inch out of the way. Remove the two long starter bolts from the rear. Drop little oily shims onto ear. Cuss. Starter falls on head. That was easy. And painful. Oh, yeah. Disconnect the battery before you start this project or you will not only be unconscious, but electrocuted as well. Next, disconnect the wires from the dangling starter. At least the above procedure always worked for me. I am used to changing starters in out of the way places such as a Wal-Mart parking lot. Of course I always did it in the dark with a dim flashlight in 32 degree weather with fogged-up glasses and metal tools frozen to my beard.
Q: Some hood tachometers are taller than others. Which is correct?
A: According to Framair (Framair@AOL.COM) "There were a few variations on the Pontiac Hood Tach. The first style was the "Tall" Style (with only 1 light inside) and the Second was the "short" style which had 2 bulbs inside. There were also variations depending on engine size (Redline changes)..6cyl, Ram Air, etc... this varied on the year. My '68 Firebird had the 'Tall' Style because it's an early car (built in Nov.'67). I would say that all '67's and some early '68's used the tall style. Have not seen any early '68 GTO's w/the Tall style so I suspect that the Firebird used the Tall style longer than the others. Mine was still attached to the 400 Hood with the Factory Rivets which were used as a theft deterrent. The latest repro's suposedly have better internals for accuracy and lighting the most noticeable feature being the plastic face which lets light go thru the face. The silk screening is a little fuzzy. Some restorers are able to re-silkscreen the face while others go with silk-screened decals."
Paul Dorton (firstname.lastname@example.org) adds: "The tall style was available factory installed on '67 models. In '68 they switched to the shorter style. One thing everyone needs to keep in mind is that not all tachs were factory installed. It was also a popular dealer installed option. If someone wanted a hood tach on his car in 68 - 69 and the dealer had a 67 tach in stock, guess what he got. And yes, the accessory kits came with the rivets and factory style wiring harness. So, looking at what is on a car, unless you have factory documentation, is not an accurate way of determinig if it came that way from the factory. Dealers did a lot of modifying back then. If you saw a car on the lot that was just what you wanted, but you didn't like a particular aspect of the car, the dealer would modify the car to your desires. At the dealer I worked at, we would even swap out the complete interior with another in stock car if you wanted a different material or wanted to update to the Custom interior. As I've said before, there were no absolutes back then."
Q:How do I change rear springs on a GTO?
A: Raymond "Bullitt" Funke (rayfunk@IDT.NET) says: "If you are changing out your shocks, you might find it easier to change the springs out too. Bad springs will wear out shocks faster, Bad springs will also wear out cheap shocks faster than expensive shocks.
To change your rear coil springs on your 68-72 A-body you: 1. Jack up the rear end, put it on jack stands, remove both tires. 2. remove lower shock nuts, 3/4 inch socket, breaker bar works wonders if you haven't done shocks in years, or live in the rust belt. Do both sides. 3. Take your jack and jack up the OPPOSITE side of the spring to be removed. This means if you are changing the right spring, jack up the left side of the axle. Jack it up as far as you can go. 4. Your spring is now loose, remove it and clean the crap off the mounting area, put the new spring in. It will not line up. This is where you choose options: a: have friend/wife/progeny/passerby slowly drop the jack while you hold the spring in place. b: put bricks under the axle side where the jack is, remove the jack, jack up the side you are working on till the spring compresses and seats properly on the mounting plate. c: quit, accept your lack of mechanical ability, accept your membership into the redneck yard club. 5. Stick more bricks under the side you are working on, remove jack, jack up other side, remove bricks. Jack up side completed, remove bricks. 6. Repeat steps 3,4,5 for opposite side. 7. Put your shocks back on, tighten them to 65 foot pounds of torque if you have a torque wrench. If no torque wrench, tighten them down as hard as you can. 8. Put the tires back on. Tighten them in star pattern. 9. Have a beer/coca-cola, you saved a basketfull of money on a spring compressor, and on paying some fool to fix your car.Estimated time for completion of job 1-2 hrs
Q:Can you help me sort out the different models?
A:Pontiac made a Tempest which was supposed to be the low end of the a-bodies. In 1969, the Tempest started out as a 6 cyl, with 350 and 350HO's as options. The Tempest Custom S was a step above it. The Custom S was available with all the typical engines, from the OHC 6 to the 350 HO. And don't forget the OHC Sprint! The custom S came in a convertible, hardtop coupe, sports coupe (hardtop coupe with a pillar strip in between the door and the 1/4 window) and 4-door. Then there's the LeMans, which came with a 6 cyl, a 350 or 350HO which was a 4bbl quadrajet version of the 350. Next up was the GTO which came with the base 400, and available with the Ram Air 400 as well. There was also a Tempest custom Safari wagon. It was a separate model from the rest. It had fancy trim and the wood grain up the sides. They started in '67 and died after only a few years. A quick look at the VIN tag will reveal exactly which model you have. Look at the first three digits. From 1965 to 1971, they went like this...
233 = Tempest
235 = Tempest Custom S
237 = Tempest LeMans
239 = Tempest Safari (wagon)
242 = GTO
Q:How can I learn more about engines?
A:PMD RACER (PMDRACER@aol.com) says: The BEST way to get A LOT of info is to get a copy of the Pontiac BIBLE that has been written by Pete McCarthy. I personally know the guy. He's a fantastic guy who used to race in Super Stock NHRA (and still does). He's one of those guys that has forgotten more about GTOs than we'll ever remember! The book is called "PONTIAC MUSCLECAR PERFORMANCE 1955 - 1979" I always take it with me to the junkyard. You have no idea how many times it saved me from passing up a valuable part, block, head, etc. He also a founder and Tech Editor for "Pontiac Enthusiast" magazine. The other book that is a necessary addition to your library is the "PONTIAC RESTORATION GUIDE 1964- 1972" Have a question of how to reassemble that thing you took apart 6 months ago? Need to know what it takes to convert over to electric windows? Paint codes, trim tags and VIN decifering, axle and trans codes, etc. It's all here. It has saved my bacon a few times! Also very useful to have when going to check out that "GTO" for sale to make sure it's a GTO or not, original colors, et al. See the link on this web site called GTO Bookstore. You can buy books online here.
Q:Can you help me decode Pontiac engine parts I find in the junkyard?
A:PMD RACER (PMDRACER@aol.com) says: To check for a Pontiac block (If it is a 1969 and later block) true CID is to pull the intake, and the valley cover. Look at the middle of the lifter bore webbing area for 1.5 to 2 inch tall numbers. If you see a "50" it's a 350, "00" is a 400, and "55" is a 455. Remember, this only works for 1969 and later blocks. For performance use on a 455, the 6X head is hard to beat. Made for the years of 1976 - 1979, they have hardened seats, screw-in rocker studs, great intake flow "out of the box", and give about a 9.6 to 1 compression ratio (perfect for street/strip). Just get the ones off of a 350. You can tell by looking at the flat on the lug on the head that is similar to the 2 lugs tapped for the A/C bracket. On the driver's side, it will be the single lug toward the radiator, on the passenger side, it will be the single lug closest to the firewall. Use a mirror and light. Look for a stamped "4" on the machined area. Those are the ones you want. If you see an "8", forget it. It's a 400 head, and the compression ratio will be too low for a 455. Make sure it is a 6X too. There are 6S and 4X heads that are not as desireable. Just keep looking in Firebids, LeMans, big cars, etc. The 6X was used in almost all models from 1976 to 1979.
Q:Can you tell me how to operate my '69 automatic "slap stick"
A:J.R. Garrett (email@example.com) says: I I have a '69 with a factory auto. It does not have a Hurst dual gate "His N Hers" shifter. What it does have is more like a ratchet shifter. There is only one slot in the console for the shift lever, unlike the Hurst His N Hers which has two separate slots for the shift lever. On the right side of the console slot, embossed into the woodgrain, are the numerals "1" "2" "3". To use the shifter in ratchet mode, depress the button on top of the shifter knob and pull it down into low. When its time to shift to second, simultaneously push forward and OUTWARD (towards the passenger side) on the lever and it will ratchet into 2nd and lock. You must completely relax the pressure on the shift lever to allow the ratchet mechanism to reset, and then when its time to go to 3rd, again push forward and outward on the lever and it will ratchet into 3rd.
A '68 His 'N Hers is a little different. There are two slots. The one on the right "his" is hidden by a chrome cover that slides out of the way. There is also no button to depress. Just ratchet the shifter up and to the right when you're shifting. It goes click into one gear without going past the next till you ratchet it again. The "hers" side is the left automatic side.
Here's a funny July 2000 post from Joshua Scholfield (firstname.lastname@example.org) ...
I took a college course a few years back, "The Societal Effects of Engineering" or some such, that was supposed to be a history class. The prof, who was in his late thirties IIRC, spent about half an hour one class period extolling the virtues of the "1958 Pontiac GTO" in ushering in the era of perormance cars. After about 10 minutes of his statements such as "the industry's first use of the fuel-injected big-block" and "grab-air hood scoops" me and my gear-head buddy could hardly keep from falling off our seats laughing. We later jointly authored an _anonymous_ term paper titled "The cultural effects of the 1958 Pontiac GTO", which we turned in with the other term papers. It consisted of the title page, a bunch of musclecar books as references, one page with the words "There was no 1958 Pontiac GTO, therefore it had no cultural impact whatsoever", and 19 blank pages to meet the 20 page minimum. Needless to say, the professor was not amused. Not that we ever really took him seriously again, mind you, but he was not amused.
- - - -
On Thanksgiving day, 2001, I wrote a message to the List and told them
some GTO-related things I was thankful for. It was a serious
note of appreciation. Comedian Keith MacDonald (email@example.com)
wrote back with his funny list of things to be thankful for...
|Thanks Sean, for those great items to be thankful
On this day I, too, often find myself feeling thankful, and I wanted to share this with others who are thankful, but uncertain about their own personal degree of overall thankfulness.
By the way, I am thankful you have read this so far...
Here are my "Things I am Thankful For -- GTO" list items:
1) I'm thankful that John DeLorean didn't work for Ford in 1963.
2) I'm thankful Pontiac used a Tiger to promote the GTO- rather than a panda bear. Somehow, "There's a panda under the hood" just doesn't work for me.
3) I'm thankful they never really produced an 8-lug GTO wheel. My back hurts just getting-off the 4 lugs on my '72. By the way, did I mention my '72 has the "One Lug -Delete" option?
4) I'm thankful that Pontiac didn't make a '78-'80 GTO with a Lemans base.
5) I'm thankful that the image of that last item (#4) didn't make me boot my rum n' eggnog.
6) I'm thankful Pontiac didn't go too heavy with the Endura bumper idea -- imagine endura seats?
7) I'm thankful that Pontiac teamed-up with Kellogg to promote the GTO -- rather than Preparation H.
8) I'm thankful that Barry Manilow never penned a GTO song.
9) I'm thankful that the Taliban aren't running around the Afghan desert in GTOs.
10) I'm thankful that I wasn't born in the mid-80's -- which automatically makes you a believer that FWD Japanese cars can have "muscle."
11) I'm thankful that skimpy bikinis go so well with GTOs in photos.
12) I'm thankful that Pontiac never produced a "Powder Blue" GTO -- like Ford did with several hundred thousand Mavericks.
13) I'm also thankful Ford never produced the butt-kickin' "Granada SHO"
14) I'm thankful that Pontiac never made a "389, Five-power." Imagine tuning five 1-bbl. carbs?
15) Finally, I'm thankful for America: apple pie, baseball, county fairs and GTOs! We are all blessed to be Americans and to be a part of this great hobby as well as this superb GTO list.
Thanks to Sean, Stephen and all of you guys for making this list as great it is.
Happy Thanksgiving to all!
Q: Where can I get my Hurst shifter serviced?
A: They can be sent to Hurst Performance; Shifter Rebuild Service; 550 Mallory
Way; Carson City,NV 89701-5374. I think they charge $ 45 for a Dual Gate.
You can call (775) 882-660 Ext 342 for info. Or go to their web page at
Attention GTO newsletter editors! Go ahead and reprint any of these Text Topics articles. Just give me credit as Sean Mattingly (Sean@UltimateGTO.com) at The Ultimate GTO Picture Site located at http://UltimateGTO.com
Here's a comment from a recent visitor...
Says Jeff Fortenberry (jefff.@coherence.com) - "It's like a vault of GTO treasures, it's quite inspiring to see some of these beautiful cars."